I am open to suggestions for additions to this list.
World Wide Words -- A fascinating site, regularly updated. Michael Quinion has written a marvelous series of short essays on topics ranging from "mondegreens" to Polari, a language spoken only in the British theatre.
Dave Wilton's Etymology Page is an excellent site that includes a very well-written and concise history of the English language as well as a fascinating exploration of the most common errors people make when trying to figure out the origins of English words. You'll also find an alphabetical index to explanations of the real origins of scores of words and phrases.
The Mavens' Word of the Day -- Started out as Jesse Sheidlower's excellent site at Random House. Mr. Sheidlower was an Editor in the Reference division of Random House, where he specialized in slang and new words. Jesse has gone on to become North American Editor for the Oxford English Dictionary, but his creation lives on, now staffed by a tag-team of witty Random House dictionary editors.
Looking for some no-nonsense take-no-prisoners grammar advice? Columbia University's Project Bartleby has put H.W. and E.G. Fowler's classic The King's English online.
Here is a very handy online dictionary from Merriam-Webster.
The alt.usage.english FAQ, maintained by Mark Israel.
The home page of The American Dialect Society.
H. Churchyard's Anti-Pedantry Page, a/k/a The Singular "Their" in Jane Austen and Elsewhere.
Wordplay, a site offering tons of links to other sites that feature "fun with words." Judi Wolinsky, the author of this page, has done a great job of assembling these links, and I will not duplicate them here. Visit this page!
Naaaaah.
We here at TWD are keenly aware of this problem, so we've woven together a rich tapestry of time-wasters for your delectation. Just visit a few of these sites, and before you know it, it'll be tomorrow.
Here we have AJR Newslink, which provides indexed links to nearly every newspaper and magazine with a web site.
As Aristotle once said (I have it on tape), the quality of a society may be judged by its rubber chickens.
Until now, finding a decent rubber chicken was nigh unto impossible, but now Archie McPhee rides to the rescue with high-quality elastic fowl and wind-up gizmos by the dozen, not to mention that fez you've been looking for.
Given up on usenet? I don't blame you. Cheer up -- there's probably a mailing list devoted to your favorite topic that you can join, and you can find it at Liszt.
I don't know how this can possibly be the Age of Disbelief when so many people believe the story about Paul Newman and the ice-cream cone. Spend a few hours at the Urban Legends Reference Pages and never be FOAFed again.
Jon Carroll's columns are always interesting.
The Literary Review, edited by Auberon Waugh and almost impossible to find on U.S. newsstands, offers sample articles from each issue online.
Who's suing AOL today? Newslinx provides constantly updated links to news stories about the net on the net.